KINGSTON • A teen killer who stabbed 14-year-old Stefanie Rengel of Toronto to death in 2008 on orders from his teenage girlfriend is charged with attempting to kill a fellow convict during a prison fight at maximum-security Millhaven Institution just west of Kingston.

David Bagshaw, 21, was charged Wednesday with attempted murder following an investigation by an OPP-led unit that probes prison crime. The victim suffered severe, but not life-threatening, injuries.

“There’s no more charges [expected] at the moment, but that’s not to say that there couldn’t be more,” said Sergeant Kristine Rae. Police are still investigating.

Police say Bagshaw was among several weapon-wielding inmates who attacked a 34-year-old prisoner in the gym on March 20. The assailants defied orders from prison guards to stop and ignored warning shots. Guards shot inmate Jordan Trudeau, 29, and Bagshaw. Trudeau died of a single gunshot wound to the chest, according to police. Bagshaw was treated at an outside hospital.

Bagshaw, who was 17 at the time he killed Rengel, pleaded guilty to first-degree murder and was handed an adult sentence of life in prison with no chance of parole for 10 years. If he had committed the crime four days later, after his 18th birthday, he could have been denied parole for 25 years.

Bagshaw argued he should have been sentenced under youth laws but his appeal was rejected by Ontario’s top court.

“Only an adult sentence properly achieves the accountability of the appellant for this horrific crime,” the Court of Appeal for Ontario ruled.

Bagshaw lured Rengel out of her Northdale Boulevard home on New Year’s Day, stabbed her six times and left her to die in the snow.

In a separate trial, jurors heard that Bagshaw acted on instruction from his manipulative girlfriend, Melissa Todorovic, who was then 15.

The sexual relationship between the teen lovers was described as being “marked by mutual obsession and jealousy.” Todorovic sent him a series of online messages, warning that she’d withhold sex or break off their relationship, if he didn’t kill Rengel. Todorovic wrongly viewed her as a rival for her boyfriend’s affection.

A jury found Todorovic guilty of first-degree murder and she was handed the maximum adult sentence allowed for a 15-year-old killer, life with no chance of parole for seven years.

Bagshaw offered a tearful apology in court to Rengel’s family.

“Nothing I can say or do can right this wrong,” he said. “I want to ask for forgiveness, but realize that I can’t even forgive myself. I hate myself and the decision I made that night.”

Psychiatrists who assessed Bagshaw said there was a good prospect of rehabilitating him and safely reintegrating him back into society but they sounded a warning, saying that he will “clearly be a challenge in the years ahead.”

One psychiatrist expressed concern about the imposition of an adult sentence. She noted that he would more likely be easily influenced in the adult prison system with the “associated increased likelihood of increasing his antisocial behaviours and attitudes.”

Bagshaw will be a candidate for transfer to a Special Handling Unit, a super-secure facility for inmates who pose a risk of killing or injuring other convicts. Inmates in the units have limited contact with other prisoners, are often confined in cells 23 hours a day and are closely watched.

Bagshaw is eligible to seek parole in January 2018, according to Corrections Canada records.